test/test_ray.dart

part of vector_math_test;

class RayTest extends BaseTest {

  Vector3 _v3(double x, double y, double z) {
    return new Vector3(x,y,z);
  }

  void testRayAt() {
    final Ray parent = new Ray.originDirection(_v3(1.0,1.0,1.0), _v3(-1.0,1.0,1.0));

    final Vector3 atOrigin = parent.at(0.0);
    final Vector3 atPositive = parent.at(1.0);
    final Vector3 atNegative = parent.at(-2.0);

    expect(atOrigin.x, equals(1.0));
    expect(atOrigin.y, equals(1.0));
    expect(atOrigin.z, equals(1.0));
    expect(atPositive.x, equals(0.0));
    expect(atPositive.y, equals(2.0));
    expect(atPositive.z, equals(2.0));
    expect(atNegative.x, equals(3.0));
    expect(atNegative.y, equals(-1.0));
    expect(atNegative.z, equals(-1.0));
  }

  void testRayIntersectionSphere() {
    final Ray parent = new Ray.originDirection(_v3(1.0,1.0,1.0), _v3(0.0,1.0,0.0));
    final Sphere inside = new Sphere.centerRadius(_v3(2.0,1.0,1.0), 2.0);
    final Sphere hitting = new Sphere.centerRadius(_v3(2.5,4.5,1.0), 2.0);
    final Sphere cutting = new Sphere.centerRadius(_v3(0.0,5.0,1.0), 1.0);
    final Sphere outside = new Sphere.centerRadius(_v3(-2.5,1.0,1.0), 1.0);
    final Sphere behind = new Sphere.centerRadius(_v3(1.0,-1.0,1.0), 1.0);

    expect(parent.intersectsWithSphere(inside), equals(Math.sqrt(3.0)));
    expect(parent.intersectsWithSphere(hitting), equals(3.5 - Math.sqrt(1.75)));
    expect(parent.intersectsWithSphere(cutting), equals(4.0));
    expect(parent.intersectsWithSphere(outside), equals(null));
    expect(parent.intersectsWithSphere(behind), equals(null));
  }

  void testRayIntersectionTriangle() {
    final Ray parent = new Ray.originDirection(_v3(1.0,1.0,1.0), _v3(0.0,1.0,0.0));
    final Triangle hitting = new Triangle.points(_v3(2.0,2.0,0.0), _v3(0.0,4.0,-1.0), _v3(0.0,4.0,3.0));
    final Triangle cutting = new Triangle.points(_v3(0.0,1.5,1.0), _v3(2.0,1.5,1.0), _v3(1.0,1.5,3.0));
    final Triangle outside = new Triangle.points(_v3(2.0,2.0,0.0), _v3(2.0,6.0,0.0), _v3(2.0,2.0,3.0));
    final Triangle behind = new Triangle.points(_v3(0.0,0.0,0.0), _v3(0.0,3.0,0.0), _v3(0.0,3.0,4.0));

    expect(parent.intersectsWithTriangle(hitting), equals(2.0));
    expect(parent.intersectsWithTriangle(cutting), equals(0.5));
    expect(parent.intersectsWithTriangle(outside), equals(null));
    expect(parent.intersectsWithTriangle(behind), equals(null));
    
    // Test cases from real-world failures:
    // Just barely intersects, but gets rounded out
    final Ray p2 = new Ray.originDirection(
        _v3(0.0,-0.16833500564098358,0.7677000164985657), 
        _v3(-0.0,-0.8124330043792725,-0.5829949975013733));
    final Triangle t2 = new Triangle.points(
        _v3(0.03430179879069328,-0.7268069982528687,0.3532710075378418),
        _v3(0.0,-0.7817990183830261,0.3641969859600067), 
        _v3(0.0,-0.7293699979782104,0.3516849875450134));
    expect(p2.intersectsWithTriangle(t2), closeTo(0.7078371874391822, 1e-10));
    // Ray is not quite perpendicular to triangle, but gets rounded out
    final Ray p3 = new Ray.originDirection(
        _v3(0.023712199181318283,-0.15045200288295746,0.7751160264015198),
        _v3(0.6024960279464722,-0.739005982875824,-0.3013699948787689));
    final Triangle t3 = new Triangle.points(
        _v3(0.16174300014972687,-0.3446039855480194,0.7121580243110657),
        _v3(0.1857299953699112,-0.3468630015850067,0.6926270127296448),
        _v3(0.18045000731945038,-0.3193660080432892,0.6921690106391907));
    expect(p3.intersectsWithTriangle(t3), closeTo(0.2538471189773835, 1e-10));
  }

  void testRayIntersectionAabb3() {
    final Ray parent = new Ray.originDirection(_v3(1.0, 1.0, 1.0), _v3(0.0, 1.0, 0.0));
    final Aabb3 hitting = new Aabb3.minmax(_v3(0.5, 3.5, -10.0), _v3(2.5, 5.5, 10.0));
    final Aabb3 cutting = new Aabb3.minmax(_v3(0.0, 2.0, 1.0), _v3(2.0, 3.0, 2.0));
    final Aabb3 outside = new Aabb3.minmax(_v3(2.0, 0.0, 0.0), _v3(6.0, 6.0, 6.0));
    final Aabb3 behind = new Aabb3.minmax(_v3(0.0, -2.0, 0.0), _v3(2.0, 0.0, 2.0));
    final Aabb3 inside = new Aabb3.minmax(_v3(0.0, 0.0, 0.0), _v3(2.0, 2.0, 2.0));

    expect(parent.intersectsWithAabb3(hitting), equals(2.5));
    expect(parent.intersectsWithAabb3(cutting), equals(1.0));
    expect(parent.intersectsWithAabb3(outside), equals(null));
    expect(parent.intersectsWithAabb3(behind), equals(null));
    expect(parent.intersectsWithAabb3(inside), equals(-1.0));
  }

  void run() {
    test('Ray At', testRayAt);
    test('Ray Intersection Sphere', testRayIntersectionSphere);
    test('Ray Intersection Triangle', testRayIntersectionTriangle);
    test('Ray Intersection Aabb3', testRayIntersectionAabb3);
  }
}